【作者】 姚中帅；

【导师】 胡明； 杨景；

【作者基本信息】 浙江理工大学 ， 机械工程， 2023， 硕士

【摘要】 随着机器人应用领域不断的深入拓展,机器人使用的交互场景越来越复杂。经典阻抗控制模式能够实现末端力和末端位置的动态平衡,同时兼顾末端力和末端位置的跟踪控制。经典阻抗控制模式中阻抗参数是预先设定的定常值,当面对外界环境位置突变或刚度突变时,无法及时响应外界突变导致瞬时接触力过大或过小。为保证复杂交互场景下的稳态力/位跟踪,本文提出一种基于模糊自适应阻抗实现力/位柔顺控制的方法。旨在根据外界环境的变化趋势,机器人末端与外界环境交互过程中呈现柔顺特性。主动响应外界环境突变及内部噪声影响,并及时做出相应的补偿,在打磨抛光等实际应用场景中可以保证待加工产品质量一致性。主要研究内容和结论如下:选取XB4机器人作为研究对象,开展XB4机器人正、逆运动学分析,并基于Matlab-Simmechanic进行仿真验证。根据牛顿-欧拉法建立机器人动力学模型,为更充分地描述机器人动力学特性,引入线性摩擦补偿动力学模型。依据动力学模型提出动力学前馈轨迹跟踪控制器,采用李雅普诺夫函数进而验证跟踪控制器的稳定性。针对XB4机器人展开动力学参数辨识,在求取基参数集的过程中引入参数归一的处理方法,有效规避相邻参数间数量级相差悬殊带来的误差影响。选取五阶傅里叶级数作为激励轨迹,配合实际物理约束及非线性优化函数确定最优的五阶傅里叶级数激励轨迹。采集关节编码器及电机电流数据,转化为关节转角及关节力矩信息。代入参数辨识框图,求解得到各关节的动力学参数。搭建计算力矩与仿真力矩对比实验平台,证明辨识得到的动力学参数符合动力学特性。将辨识的动力学参数引入动力学前馈轨迹控制框图中验证轨迹跟踪效果,根据跟踪效果证实动力学前馈可以补偿动态特性及提高轨迹跟踪精度。提出基于模糊自适应的力/位柔顺控制方法,根据反馈接触力及接触力变化率实时调整阻抗因子,实现末端接触力与末端位置之间的动态平衡关系,使机器人末端与外界环境接触时呈现柔顺性。在Matlab中建立Simulink框图分析该控制方法下恒力、正弦力跟踪效果及位置跟踪效果,搭建力/位柔顺实机控制平台。分别设计平面及弧面两种打磨工况,验证基于阻抗控制的力/位柔顺控制实效性。更多还原

【Abstract】 With the continuous in-depth exploration of robotic application field,the interactive scenes used by robots become more and more abundant and complex.The classical impedance control mode can achieve the dynamic balance between end force and end position while considering both end force and end position tracking control.In classical impedance control mode,impedance parameters are invariable when facing sudden change of position or rigidity of external environment.In order to ensure steady-state force tracking in complex interactive scenes,a method of force compliance control based on fuzzy adaptive impedance is proposed in this paper.The aim is to show compliance characteristics according to the changing trend of external environment,actively respond to sudden changes and disturbances of external environment and timely make corresponding compensation measures to ensure product quality and consistency in grinding and polishing applications.The main research contents include:The XB4 robot was analyzed in forward kinematics and inverse kinematics,and simulated and tested based on the MATLAB simulation mechanism.The dynamic model of the robot is based on the Newton Euler method.A more detailed description of the dynamic properties of the robot,a linear friction compensation dynamic model is introduced.A dynamic feed-forward trajectory tracking controller is proposed based on the dynamic model,and its stability is verified using Lyapunov functions.In order to identify dynamic parameters of XB4 robot,a parameter normalization method is introduced in the process of obtaining the base parameter set,which can effectively avoid the error caused by the great difference of magnitudes between adjacent parameters.Select the fifth order Fourier series as the excitation path to determine the optimal excitation path for the finite term Fourier series with actual physical constraints and nonlinear optimization functions.The current data of joint encoder and motor are collected and converted into joint rotation angle and joint torque information.It is taken into the parameter identification block diagram to obtain the dynamic parameters of each joint.To verify the identified dynamic parameters above,a comparison experiment between calculated and simulated torques is established.The results show that the calculated torque of the identified dynamic parameters has the same trend as that of the simulation experiment,which means that the identified dynamic parameters conform to the dynamic characteristics of the real machine.In order to study the impact of different impedance parameters on system stability,a force flexible control method based on fuzzy adaptive control is proposed.Simulink block diagram is established in Matlab to analyze the effect of constant force,sine force and position tracking under this control method,and a force level compliance control platform is built.Two grinding conditions,plane and surface,are designed to verify the effectiveness of force level compliance control based on fuzzy adaptive control.更多还原